诱导子对红豆杉培养细胞紫杉醇产量的影响

利用红豆杉细胞培养技术生产紫杉醇是目前紫杉醇生产的研究热点之一,并已取得了较大进展,其中如何提高紫杉醇的产量是研究的关键。目前通过促进紫杉醇代谢来提高产量最常用、最重要的方法之一是添加诱导子。这是来源于病原微生物的一类化学物质,具有诱导植物细胞中防卫基因表达诱发植物过敏反应和促进植物细胞中特定次生代谢产物的合成等多种功能。就近年来在红豆杉细胞培养生产紫杉醇方面的研究进展进行简要论述,着重介绍了添加诱导子在促进紫杉醇生物合成中的应用。     

植物细胞工程技术生产紫杉醇研究进展

紫杉醇是一种二萜类生物碱,主要从红豆杉树皮中分离提取。目前采用植物细胞工程技术是提高紫杉醇产率、保护稀缺资源红豆杉、解决紫杉醇药源紧缺的一种最有效方法。该文对近十年来国内外有关采用植物细胞工程技术生产紫杉醇的研究进展,包括红豆杉细胞系的建立、悬浮培养条件的研究、生物反应器培养以及紫杉醇合成代谢调控方面的最新研究进展进行综述。并重点论述了前体、诱导子和代谢支路抑制剂对红豆杉细胞悬浮培养生产紫杉醇的影响,为植物细胞工程技术生产紫杉醇提供借鉴和参考。     

脂氧合酶在诱导红豆杉细胞产紫杉醇中的作用

对红豆杉悬浮培养细胞中脂氧合酶(LOX)在诱导子诱导紫杉醇合成中的作用进行了探讨。结果表明真菌诱导子处理可提高细胞内LOX的活性和紫杉醇的产量,而诱导前用LOX抑制剂菲尼酮处理,可完全抑制诱导子对LOX活性和紫杉醇合成的诱导作用。说明LOX途径可能参与了紫杉醇的合成过程。外加茉莉酸甲酯也可激活LOX活性和紫杉醇合成,诱导前用菲尼酮处理可抑制诱导子诱导的LOX活性和紫杉醇合成,说明外源茉莉酸甲酯可能是通过激活细胞内LOX途径而启动下游紫杉醇的合成。为了进一步研究脂氧合酶在紫杉醇合成中的作用。我们还对红豆杉细胞脂氧合酶的分布和分子量等性质进行了研究。     

水杨酸对真菌诱导子诱导红豆杉悬浮细胞膜脂过氧化和紫杉醇生物合成的影响

研究了 5 0 mg· L- 1真菌诱导子 (F5) ,5 0 mg· L- 1水杨酸 (SA) ,5 0 mg· L- 1F5+5 0 mg· L- 1SA3种处理 ,对红豆杉悬浮细胞膜脂过氧化和紫杉醇合成的影响。结果表明 :F5和 SA单独处理红豆杉细胞均引起细胞膜脂过氧化。SA+F5联合处理可以减轻 F5单独处理细胞所引起的膜脂过氧化程度 ,SA+F5联合处理与真菌诱导子处理相比 ,较大地提高了过氧化物酶的活性 ,得到较多的生物量。3种处理方法均可提高红豆杉细胞紫杉醇产量 ,特别以 F5+SA处理得到产量最高 ,达到 1 1 .5 mg· L- 1,分别为 F5,SA和对照组的 1 .5倍、2 .0倍和7.5倍。结果显示 :在真菌诱导子诱导与水杨酸的联合作用下提高紫杉醇产量 ,可能与水杨酸减轻真菌诱导子所引起的细胞膜脂过氧化程度有关     

诱导子在红豆杉细胞培养生产紫杉醇中的应用研究进展

诱导子作为一种调控植物次生代谢产物生物合成的重要手段,用于红豆杉(Taxus)细胞培养生产紫杉醇的研究效果显著。本文分别就生物诱导子和非生物诱导子促进紫杉醇生物合成及其可能的作用机制进行了综述。     

诱导子在红豆杉细胞培养生产紫杉醇中的应用研究进展

诱导子作为一种调控植物次生代谢产物生物合成的重要手段,用于红豆杉(Taxus)细胞培养生产紫杉醇的研究效果显著。本文分别就生物诱导子和非生物诱导子促进紫杉醇生物合成及其可能的作用机制进行了综述。     

几种真菌诱导子对云南红豆杉细胞产生紫杉醇的影响

自１９９３年以来,紫杉醇（Ｔａｘｏｌ）已成为临床上治疗乳腺癌和卵巢癌的重要药物。由于其药源植物—红豆杉属植物（ＴａｘｕｓＬ．）生长非常缓慢,体内紫杉醇含量很低,且资源有限,所以人们一直在寻找解决紫杉醇药源短缺的方法。用红豆杉属植物组织培养技术生产紫杉醇被认为是一种有潜力的方法之一,受到人们的高度重视。虽然有关这方面的报道较多［１］,但该研究仍处在试验阶段,还未见用此方法商业化生产紫杉醇的报道。其重要原因是目前红豆杉属植物离体细胞的紫杉醇产量还比较低,而且不稳。人们仍在继续寻找提高紫杉醇产量的方法…     

真菌诱导子对中国红豆杉生产紫杉醇优化模型研究

采用均匀设计,研究了真菌诱导子F5质量浓度,添加阶段与处理时间等对中国红豆杉细胞生产紫杉醇（Taxol）的综合效应,建立了以紫杉醇产量为目标函数的数学模型,借助模型,研究了各因子及其交互作用对紫杉醇含量的影响,获得了第15d加入质量浓度为0.64mg/L的真菌诱导子F5,处理29d为最佳的工艺组合。     

担子菌及其木质纤维素降解液在红豆杉细胞培养中的作用

研究了担子菌及其木质纤维素降解液在红豆杉细胞培养中的作用,结果表明,担子菌Ｂｄｓ及其木质纤维素降解液制备的诱导子对紫杉醇生物合成具有明显的促进作用,且以木质纤维素发酵致第７天的降解液对紫杉醇生物合成的诱导作用最明显。因此,可以用担子菌Ｂｄｓ发酵木质纤维素所得的降解液制备紫杉醇生物合成的诱导子。     

红豆杉细胞周期时相与紫杉醇诱导合成的关系初探

利用植物细胞培养生产药用次生代谢产物 ,普遍存在着次生代谢物产量不稳定的问题。次生代谢物是一大类无明显生理功能或者非生长发育所必需的小分子有机化合物 ,其生物合成与积累一般发生在植物某些器官和组织发育的某个时期。因此 ,植物细胞的生长发育状态与次生代谢物产量有密切的关系。细胞周期时相在很大程度上反映细胞本身所处的状态 ,对细胞周期时相进行调控可能对次生代谢物产量具有重要影响 [1 ] 。诱导作用是提高植物次生代谢物产量的有效方法之一 [2 ,3]。我们以 2种经典同步化方法 ,建立红豆杉悬浮细胞初始周期时相模型 ,对不同…     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.